big man

Got a 71 cutlass 455. I can't keep it cool at all. My current setup includes 2 derale electric fans rated at 4k cfm with shroud, a high flow water pump and an aluminum radiator that I feel is underperforming. I'd like to upgrade to a 3 core but before I spend the big bucks I was thinking of just going back to the stock setup of clutch and fan, which to me is more reliable anyway instead of having to worry about fans and relays working and leaving me stuck.
My questions are what is a good clutch and fan to use? I'd like the fan as big as possible too. I've went from 180 thermostat to 160 thermostat and still no change. Temps still get to 215 before I panic and cut it off
455, mild cam 226/230, headers, performer intake and sniper efi. 391 gears, 2004r.
Thanks guys for any suggestions

Kada

What heads are you using and what is your compression ratio?

big man

edelbrock heads. Compression hasn't been measured but with the piston and gasket bottom end combo it's 'supposed' to measure 9.5 or 9.6. It's been a while can't remember exactly..

olds 307 and 403

Specs on the radiator?

big man

2 core radiator. Not sure which brand. Not too thick of a radiator but was going to go in front of my 350 instead of my 455

oldcutlass

Is the 215 at idle or cruising?

rocketscientis

Used to be a retarded timming was #1 cause
now its cheap as stamped steel impellers...th enginers knew what they were doin ...unlike most water pump rebuilders...quality somehow has come to mean good enough that someone will buy it
When th cast iron impeller on pump is replaced with a stamped steel impeller & a under 2" inlet is employed on th casting , no good cooling will be obtained...hav a selection of OEM 6 or 7 bladed , clutched fans but th heart of your coolin system is th pump
Seldom seen yet still possability is junk outa th box thermostat
Never instal one without boilin it to see if it works properly....racecars & my racewrecker employ a washer with correct size hole so engine temp is where it should b & old faithful stays in yellowstone...not under my hood
Olds engines dont live well hot.....let it set....you'll get another 60 minutes next hour...but when can u get nuther BBO ?...& walkun aint crowded....

big man

More so at idle. When I cruise I can hear the fans calm a little bit but when idle after a fairly decent drive those fans are screaming.

oldcutlass

I would go back to a stock set up as your fans are not keeping up with demand. The other thing is timing and if your engine is running lean can contribute to heat.

green1972

Check timing, and air fuel ratio, ^ richen at idle and test, Tim

olds 307 and 403

Either a 4 core or even better, a 2 core with 1"+ core size is a good idea. Auto City, 1 1/8" and Cold Case 1 1/4" two core rads, even have stock looking stamped tanks.

myhoney

Does your lower radiator hose have the spring internally to prevent the hose from collapsing?

Fun71

That is what I'm thinking as well.

Sugar Bear

Are the fans pulling air? I've seen them wired reversed from the factory...

A standard two row rad sounds light for the task. Shoot the rad with an infrared looking for cool spots that are blocked internally not dissipating heat.

Good idea to change the thermostat; but, remember, a properly operating thermostat only controls the minimum operating temp. Boiling it and watching it tells when it opens and if it opens completely.

Good luck!!!

danktx

Before you tear apart the cooling system I'd use THERMO-CURE to clean the cooling system. My 455 was a fresh build and the water turned black from the rust that dissolved into the water. When looking in the radiator the deposits at the end of the cooling tubes disappeared.

I've got a 455 without a shroud, seven blade fan with new clutch hub, 3 row copper radiator. It runs at the thermostat temperature in Texas in 100+ heat. That being said when I first got the engine running I tried connecting the vacuum advance to ported vacuum and the car ran at over 205 degrees. I'm running 16 deg initial with 19 deg mechanical and have the vacuum advance limited to 11 deg.

This works for me. Good luck...

big man

I just checked out auto city. Those are affordable. I may go that route, thanks

yes, it's functioning properly

I'll go with a larger radiator and see what happens. If it doesn't work then I'll do a stock setup and go back to the drawing board

I did check the thermostat and the fans do pull a lot of air. It will move your shirt when your standing by the master cylinder.

Thanks for everyone's help I've got some good ideas flowing now starting with the radiator which seems to be too small for the 455... Possibly

big man

I'll keep that in mind, thanks. I did flush out the block but not the radiator. Don't know why it must of slipped my mind that day

oldcutlass

I run a single row 1 1/4 core aluminum radiator with plastic tanks and 1818 flexalite mechanical fan with no shroud. My temps are pretty steady at 190* with a 180* thermostat. On a 100+ day it may creep a bit at idle. Again with your FI setup, double check to make sure your not running leans and that your timing map is correct before changing the cooling system.

big man

Just an update. I finally got the temps down on the 455. I'm glad you showed me the autocityclassic website. I ended up getting the 2 core radiator with the larger cores in it. Roughly $230 to the door, and it only took a couple days and it was in. Very happy with it and I feel more relaxed driving it instead of staring at the temp gauge the whole time.
Come to find out I only had a 1 core in it the whole time so I knew when I put this in it should do the trick.
While driving my temp is at 185 stop light to stop light. On the highway it ranges from 177-180 which is great. I'll stick with electric fans till they break and then I'll go to clutch fan and be done.
Hi flow water pump, 160 thermostat, 2 core radiator, and derale fans with shroud, 4000 cfm.
Thanks for all the help and suggestions...

oldcutlass

Thanks for the positive update.

cruiser 88

I had the same set up with the dual electric fans and a dual 1” core aluminum rad. I found that after driving mine a while the temp would start to rise especially on hotter days and I couldn’t get the temp to go down till I was moving at a good speed for awhile. I went back to a mechanical flex fan and noticed prob twice the air pulling throught the rad and never again had it clime past 185 deg. BB 455 get warm especially if you run the stock intake. A dual core rad is a good thing but I’ve found that electric fans don’t work well for big blocks. Either way though if you got it working the way you want it to that’s all that matters! Nothing rolls like an olds!